Stopper holder for a casting ladle

ABSTRACT

The holder uses two parallel links to control the lifting and lowering of the stopper. The lower link is longer so as to pivot with a longer pivot arm. This allows the stopper to move as straight as possible. Also, the actuating lever is connected over a toggle to the upper link so that a relatively great force is applied to lift the stopper initially with a small movement of the toggle. This allows fine metering of the casting stream.

. United States Patent [191 3,744,684 Heimgartner [4 July 10, 1973 [54] STOPPER HOLDER FOR A CASTING LADLE 3,331,539 7/1967 COfGl' 6t ZZZ/DIG. 5 [75] Inventor: Julius Heimgartner, SulbAttikon, 2,668,994 2/ 1954 Hansen ZZ-ZIDIG. 5

Switzerland FQREIGN PATENTS OR APPLICATIONS [73] Assignee; Sulzer Brothers Ltd, winterthu 1,101,829 l/l968 Great Britain ZZZ/DIG. 5

Switzerland 22 F1 d: 27 1971 Primary ExaminerSamuel F. Coleman 1 l e 0 Oct Assistant Examiner-David A. Scherbel [2i] Appl. 192,960 Attorneyl(enyon & Kenyon Reilly Carr & Chapin [30] Foreign Applleation Priority Data [57] ABSTRACT Dec. 4, l970 Switzerland 17966/70 The holder uses o parallel links to contr the n g 52 US. Cl 222/509 222/559 251 232 and l"waning swPPer- The link is 51 int. Cl B220 37/00 as Pivot with a P This the P' [58] Field of Search 222/563 DIG. 5 P Straight as Possible. Al), the actuating 222/559 251/232 lever is connected over a toggle to the upper link so that a relatively great force is applied to lift the stopper [56] References Cited initially with a small movement of the toggle. This al- UNITED STATES PATENTS lows fine metering of the casting stream.

1,871,333 '8/1932 McKune ZZZ/DIG. 5 4 Claims, 4 Drawing Figures STOPPER HOLDER FOR A CASTING LADLE This invention relates to a stopper holder for a casting ladle.

Casting ladles having a bottom outlet have usually been provided with a stopper which has been displaceable vertically within a holder through the intermediary of a stopper rod and by means of an actuating element. Such holders have also been used with casting pans and smelting furnaces. However, the known stopper holders and the actuating elements have generally had approximately constant transmission ratio between the travel of the stopper and the travel of the actuating ele ments. Because of this, it has been virtually impossible to make a fine adjustment of the casting stream.

Accordingly, it is an object of the invention to provide a stopper holder with which fine adjustment of a casting stream is possible.

Briefly, the invention provides a holder in which a stopper rod is fastened in an articulated manner to a holding column outside the casting ladle by means of two rocker-links spaced vertically apart from one another. The rod is guided during the raising and lowering of the stopper and is characterized in that an elbowlever, i.e., a bell crank, or toggle lever, is linked to one of the two rocker-links and connected to an actuating element for moving the stopper-rod.

By using, a bell crank a transmission ratio is obtained between the stopper lift and the travel of the actuating element that is adapted to the stopper position. In the case of a small stopper opening, this ratio is relatively large and decreases as the lift increases. This, however, means that at the beginning, for a short travel and a great force at the stopper, a relatively great travel and small force have to be applied to actuating lever. As a result, it is possible to easily open a sticking stopper and to obtain fine regulation of the casting stream. Further, during closure, a slow and smooth seating of the stopper is possible. Thus, the danger of damaging the stopper-head and of a discharge are decreased.

It is moreover desirable that the stopper-head, as in the case of conventional mechanism, shall lift practically precisely along the axis of the run-out of casting metal. This is obtained with the holder in that the pivot arm of the upper rocker-link is smaller than that of the lower link. Thus, assuming a small lift of the stopper, e.g. for a ratio of distance lifted relative to the pivot arm of the lower link of 1:5, the lengths of the two pivot arms are related to one another in inverse propor' tion to their distance from the lower edge of the stopper.

It is furthermore advantageous for the stopper to be automatically locked after installation in the casting ladle to prevent accidental lifting from the stopper side, and to be automatically unlocked without having to loosen screws or wedges upon being opened from the actuating side. It has therefore proved desirable to pro- FIG. 1 illustrates a holder of the invention wherein a bell crank and an actuating element are shown by solid lines in the closed position of the stopper, and are shown by dot-dash lines with the stopper lifted;

FIG. 3 illustrates a view taken on line III-lll of FIG. 1; and i .FIG. 4 illustrates a schematic representation of the travel of the stopper-rod and of the rocker-links during a certain lift h.

The casting ladle I which is generally made of sheetsteel is depending on the temperature and the aggressiveness of the molten material to be cast, providedor not with a lining 2 of ceramic material, for example Al- 0 The bottom 3 of the ladle 1 has an outlet opening and a screw 9 which fastens the rod 7 in place relative vide one pulling element and at least one stop in the lever system through which the articulation points of the bell crank are in the closed position of the stopper held in a straight line at least. The pulling element compensates the weight of the actuating lever, and thus prevents the stopper from unlocking itself.

These and other objects and advantages of the invention will become more apparent from the following detailed description and appended claims taken in conjunction with the accompanying drawings in which:

to the sleeve 8. Two diametrally opposite pivot-like protrusions 10 and 11 are located on the outside of the sleeve 8 at two pivot points separated from each other vertically by the distance b (FIG. 4).

In addition the holder includes aholding column 16 which is pushed into a guideway 17 on the outside of the ladle 1 so as to be vertically adjustable relative to the ladle and a screw 18 which fastens the column 16 in place relative to the ladle I. The column 16 has a fork-like shape and mounts a pair of mounting bolts 27 therein to define pivot points 12 and 13. As shown in FIGS. 2 and 3, each bolt 27 passes through the column 16 through a sleeve 25 and has screw threaded ends which project out of the sleeve 25 and column 16. Each sleeve 25 is mounted in the column 16 and has reduced ends which project from the column 16. The screw threaded ends of the bolts 27 have washers 26 mounted thereon as well as threaded nuts 19 which serve to secure the bolts 27 in place.

The two upper pivot-points I0 and 12 are connected with one another by an upper rocker-link 14; while a lower rocker-link 15 serves to connect the lower points 11 and 13. Both rocker-links l4, 15 are made of two flat irons pushed on the protrusions at the pivot points 10 and II of the sleeve 8 and on the reduced ends of the sleeves 25, respectively. The two rocker-links l4, 15 together form, along with the sleeve 8 connecting them and with the pivot points 10 to 13, an articulated quadrilateral for guiding the stopper-rod 7 during liftmg. a

A lever system engages with the point 13 of the lower link 15 for the operation of the stopper 6. This lever system consists of an actuating lever 20 which merges at its lower end in the region of the pivot point 13 into a fork-like connecting piece 21 (see FIG. 3). The free end of the connecting piece 21 has a pivot point 22 which once more consists of a sleeve 25, a bolt 27 and nuts 19 with washers 26, and a connecting part 23 is secured thereto. The connecting part 23 is able to pivot and is, in turn, connected at the other end with the FIG. 2 illustrates a view taken on line II-Il of FIG.

upper link 14, through the intermediary of the same elements 25, 26, 27 and 19, at a pivot point 30.

The connecting part 21 and the part 23 form a bell crank or toggle lever with the pivot point 22 which is, as well known characterized by an articulation, the socalled knee, between two one-arm levers; the other ends each being mounted in a further link, in this case forming the pivot points 13 and 30. As is well known, the working of the toggle lever is that when a force is applied to the knee joint, the force produced by its component acting perpendicularly to the line connecting the outer joints in the direction of this connecting line increases as the angle between this connecting line and the one-arm lever becomes smaller.

A spring 28 is stretched between the upper end of the holding column 16 and the actuating lever 20 as a pulling element to continuously'pull the lever 20 upward. Thus, through the intermediary of the fork-like connecting part 2l'and the connecting part 23, the stopper 6 is pressed into its position of rest against the bottom outlet 4. In this condition, the part 23 is pulled against a stop 29 disposed in the bottom of the fork of the connecting part 21 and suited to the lever system in such a way that, in the position of rest, the pivot points 22, 13 and 30 lie on a straight line at least as shown in FIG. 1, the pivot points 22, 13, 30 form an angle of less than 180 which lies with point 13 as the vertex and which opens to the upper right as viewed when the stopper 6 is lifted.

It is self-evidently possible for the pivot point 22 to be set above the straight line through the points 13 and 30. In this way, and by the aid of the spring 28 and the stop 29, self-locking of the stopper 6 in its closed position is obtained so that the stopper 6 cannot be lifted by an upward or some other force. A supplementary locking of the stopper is thus not necessary.

As has already been mentioned, it is desirable that the stopper 6, in spite of the circular movement of the points and 11, to be lifted in as straight as possible a line out of the outlet 4. This purpose can be achieved when the pivot arm r of the upper link 14 is a certain amount smaller than the arm a of the lower link 15.

Referring to FIG. 4, during lifting of the stopper 6 by the height h, the points 10, 11 of the two links 14, move about the points l2, 13. As shown for the pivot arm of the upper link 14 designated by r, the pivot arm for the lower link 5 designated by a, the spacing apart of the pivot arms designed b, the spacing of the lower link 15 from the lower rim of the stopper 6 designated c, and the spacing of the upper link 14 from the lower rim of the stopper 6 designated d c b, by a simple computation, the value r is obtained by the formula given at the bottom of FIG. 4. Under the assumption that h 2 l/5-a or that h c and c b (a condition always met in practical operation), the formula shown at the bottom of FIG. 4 becomes simplified, since (1 cosdi) 0, to

In operation, the lifting of the stopper 6 is accomplished by pressing down the lever 20, which can be done by hand or else by some suitable mechanical, hydraulic, pneumatic or electric or electromagnetic drive. By being pivoted in this way about the fixed point l2,

the lever 20 moves against the force of the spring 28 into the position shown by dot-dash lines in FIG. 1. The points 20, 30, 10 and 11, and also the stopper 6, are thus displaced into the position also shown by dot-dash lines. The upward lift of the stopper 6 can be limited by a stop 31 in the form of a cylindrical pin between the two flat-irons of the link 15 against which the connecting part 23 abuts. Because of the illustrated bell crank or toggle-lever action, relatively great forces act initially with a small movement of the knee-lever when the stopper is closed, so that even stoppers which stick can be, opened easily. Also, during the initial phase of opening, the travel of the point 30, and thus the lift effected at the stopper 6, is relatively small as compared with the angle through which the lever 20 is turned, so that fine metering of the casting stream is obtained.

Computations of the lateral deviation of a holder, to which apply the foregoing assumptions as to the lift h, the pivot arm a, and the spacings c and d, and with a lift for'th'e stopper 6 such as is in practical use, show, apart from deviations caused by play and finishing tolerances, a deviation of the outflow axis of only a fraction of a millimeter.

What is claimed is:

1. A stopper holder for a casting ladle having a bottom outlet comprising:

a holding column for securement relative to the ladle;

a sleeve spaced from and parallel to said column for mounting a stopper rod therein;

a pair of rocker links, each pivotally connected at one end to said column and at an opposite end to said sleeve, said links being vertically spaced from each other;

a toggle lever linked to one of said rocker links; and

an actuating lever linked to said toggle lever at one end thereof whereby upon downward movement of said actuating element said toggle lever pivo'ts said one rocker link to lift said sleeve in a substantially vertical direction.

2. A stopper holder as set forth in claim 1 wherein the upper rocker-link of said rocker links is of shorter length than the pivot am (a) of the lower rocker-link of said rocker links to have a smaller pivot arm, whereby, assuming a short travel (h), of the stopper rod a ratio of distance h to pivot arm a of 1:5, the lengths of said two pivot arms are inversely proportionally to their spacings from the lower edge of a stopper on said stopper rod.

3. A stopper holder as set forth in claim 1 which further includes a pulling means for biasing said actuating element in a closing direction and a stop for limiting a closing motion of said holder.

4. A stopper holder as set forth in claim 1 wherein said toggle lever is pivotally mounted on said rocker link at a first pivot point, an actuating lever is pivotally mounted on said column at a second pivot point and is pivotally conected to said toggle lever at said second pivot point, and said toggle lever has two parts pivotally connected at a third pivot point, said pivot points lying in a straight line with said stopper rod in a closed position and forming an angle of less than which lies with said first pivot point as the vertex and which opens towards said rocker tube when said sleeve is lifted. 

1. A stopper holder for a casting ladle having a bottom outlet comprising: a holding column for securement relative to the ladle; a sleeve spaced from and parallel to said column for mounting a stopper rod therein; a pair of rocker links, each pivotally connected at one end to said column and at an opposite end to said sleeve, said links being vertically spaced from each other; a toggle lever linked to one of said rocker links; and an actuating lever linked to said toggle lever at one end thereof whereby upon downward movement of said actuating element said toggle lever pivots said one rocker link to lift said sleeve in a substantially vertical direction.
 2. A stopper holder as set forth in claim 1 wherein the upper rocker-link of said rocker links is of shorter length than the pivot arm (a) of the lower rocker-link of said rocker links to have a smaller pivot arm, whereby, assuming a short travel (h), of the stopper rod a ratio of distance h to pivot arm a of < or = 1:5, the lengths of said two pivot arms are inversely proportionally to their spacings from the lower edge of a stopper on said stopper rod.
 3. A stopper holder as set forth in claim 1 which further includes a pulling means for biasing said actuating element in a closing direction and a stop for limiting a closing motion of said holder.
 4. A stopper holder as set forth in claim 1 wherein said toggle lever is pivotally mounted on said rocker link at a first pivot point, an actuating lever is pivotally mounted on said column at a second pivot point and is pivotally connected to said toggle lever at said second pivot point, and said toggle lever has two parts pivotally connected at a third pivot point, said pivot points lying in a straight line with said stopper rod in a closed position and forming an angle of less than 180* which lies with said first pivot point as the vertex and which opens towards said rocker tube when said sleeve is lifted. 